The operators of such stations generally lease the facilities from a proprietor, sharing in the proceeds, and/or obtain the products on a commission basis from a supplier. Thus, moneys collected by the station operator must be accounted for to such proprietor or supplier, e.g. by being delivered to a bank safe or other depository which can be emptied only by the recipient. The latter, obviously, is interested in promptly receiving these payments and avoiding an excessive accumulation of cash at the filling station.
Self-service stations are known in which a customer inserts bills or coins into a register which thereupon releases a corresponding quantity of fuel. If the register is designed to receive paper money, the bills are scanned by a testing head which verifies their genuineness and discriminates among different denominations. Thus, there exists an exact correlation between fuel volume and amount paid, with no provision for credit or overdraft. These devices, accordingly, are not suitable for transactions between the operator of a filling station and a supplier delivering fuel on credit or commission.